Self-leveling devices



March 3, 1964 1. BRONSON SELF-LEVELING DEVICES 3 SheetsSheet 1 Filed Oct. 26, 1960 FIG. I

March 3, 1964 1. BRONSON SELF-LEVELING DEVICES 3 Sheets-Sheet 3 Filed Oct. 26, 1960 FIG. 5

INVEN TOR. /e WA/ 8190 490 United States Patent 3,123,024 SELF-LEVELING DEVICES Irving Bronson, Brooklyn, N.Y., assignor, by mesne assignments, to American Machine & Foundry Company, New York, N.Y., a corporation of New Jersey Filed Get. 26, 1960, Ser. No. 65,137 6 Claims. (Cl. 168-136) This invention relates to a self-leveling device for receiving, storing and dispensing articles.

This application is a continuation-in-part of my copending applications Serial Nos. 49,856, 49,857 and 49,912, all filed on August 16, 1960.

Under many circumstances, it is desirable to dispose a series of articles in stacked relation upon a wheel-mounted carrier and to remove said articles therefrom as desired. Thus, for example, restaurants or similar food service institutions may require that a series of dish racks be stacked as they are removed from a dishwashing machine and thereafter transported to another location at which the racks are unloaded as required. In this, as well as in many other applications, it is quite important that the loading and unloading points he maintained at a constant level regardless of the number of stacked articles disposed upon the carrier in order to minimize the amount of effort required and to maintain the uppermost rack or article at the most desirable level. Although self-leveling devices of this character have been suggested, they have been characterized by shortcomings which are overcome by the instant invention.

It is therefore an object of this invention to provide a self-leveling device for receiving, storing and dispensing articles which is simple in arrangement and construction and which effectively maintains a plurality of articles in stacked relation, with the uppermost article being maintained at a predetermined level regardless of the number of articles comprising the stack.

Another object of this invention is to provide a selfleveling device of the character indicated which may be readily adjusted to accommodate various stacks of articles as when it is desired to change over from a stack comprised of articles of a certain weight and vertical dimension to a stack comprised of articles of a different unit weight and vertical dimension.

It is also an object of this invention to provide a device of the character indicated wherein it is not necessary to employ special types of spring elements in order to provide for the maintenance of a stack of articles at a predetermined constant level regardless of the number of articles comprising the stack and variations in the characteristics of the group.

An additional object of this invention is to provide an arrangement wherein a stack elevating spring arrangement is employed which provides for varying the leverage exerted upon the spring means to accord with the degree of winding or unwinding thereof. It is a further object to provide means for adjusting the initial spring tension and degree of leverage exerted thereon.

This invention also has for its object the provision of a device of the character indicated wherein positioning means are provided for accurately locating the uppermost article of the stack at a predetermined elevation.

ther and further objects of this invention will become apparent from the description thereof contained in the annexed specification, or will otherwise become obvious. It will be understood that the invention here disclosed may be employed for other purposes to which the structure and arrangement are adapted.

In the accompanying drawings:

FIGURE 1 is a side elevational view of a self-leveling device embodying the features of the instant invention,

ice

partly in section and also showing the carrier platform under load in broken lines;

FIGURE 2 is a fragmentary side elevational view of the upper portion of the self-leveling device depicted in FIGURE 1;

FIGURE 3 is a fragmentary plan view of the form of the invention depicted in FIGURE 1;

FIGURE 4 is a fragmentary side elevational View of one of the carriage assemblies employed in said form of the invention, said carriage assembly being shown partly in section and being in operative association with one of the upright frame assemblies provided in said form of the invention;

FIGURE 5 is a cross-sectional view taken about the line 5-5 of FIGURE 1;

FIGURE 6 is a cross-sectional view taken about the line 6-6 of FIGURE 5; and

FIGURE 7 is a fragmentary side elevational view of one of the carriage assemblies employed in said form of the invention, said view being similar to that depicted in FIGURE 4 but showing the spring member employed in connection with said carriage assembly wound to a position wherein it exerts a substantially greater torque than it does from the position depicted in FIGURE 4.

A self-leveling, receiving, storing and dispensing device embodying the features of the instant invention is illustrated in FIGURE 1 of the accompanying drawings. As may be seen from said figure, the device comprises a wheel-mounted base assembly, designated generally by the numeral 10, which supports an upright frame as sembly, designated generally by the numeral 11. A carrier assembly, designated generally by the numeral "12 and disposed forwardly of the upright frame assembly, receives, stores and dispenses the desired articles and is mounted for vertical movement on the upright frame assembly 11. Articles, such as dish racks for example, are stacked upon the carrier platform 12a of the carrier assembly and with the placement of each successive rack thereon, the stack is depressed or lowered so that the uppermost article in the stack is always at the same working level. Conversely, as each article is successively removed from the stack, the entire remaining stack is elevated so that the next succeeding article is brought up to the desired working level.

The base assembly 1% in the form of the invention illustrated comprises a generally rectangular frame 13 which is advantageously formed of angle members of steel, aluminum or other suitable material. The frame is further provided with casters 14, which are mounted adjacent the corners of the base. By forming the base in the manner indicated, it is possible to make use of this portion of the device for further storage of used racks for example. Thus, as a new rack is removed tfrom the stack upon the carrier platform which is elevated as a consequence of such removal, a used rack may be disposed upon the frame assembly in the space thus formed.

The upright frame assembly 11 is mounted upon the Wheeled base 1-1? and comprises a pair of ventical trackways 15 and 16, disposed on the opposing sides of the base frame 13. Each of trackways 15 and 16 comprises guide rails 17 having flange portions 18 and head portions 19. On each side of the base assembly an inclined brace member 2'3 extends from the base to the upper portion of the guide rails, thereby supporting the said tracnways.

Each of the guide rails receives a vertically movable carriage assembly which supports an important feature of this invention residing in the means for presetting a spring drum so as to provide a predetermined resistance to variation in the level of the carrier platform 12a.

Thus, as may be seen by references to FIGURES 1 to 3, the upright frame assembly houses :a pair of rectangular carriage plates 21 between which is disposed a transverse hollow drum 22. At each end of this drum, a bushing 23 is threadedly engaged with said drum 22 and houses a ball bearing 24 which rotatably secures a shaft 25. Intermediate of said bearings 24 are provided a pair of flanged collars, generally designated by the numerals 26, 27, the bodies 28 of said collars 26, 27 being formed with grooves 29 to receive a coiled torsion spring One of the collars 26 is secured to the shaft 25 by a radially disposed pin 31 and the other of said collars 27 is rotatable with respect to the shaft 25. The ends of the aforesaid coiled torsion spring 31 are also suitably affixed to the collars so that any rotation of the collar 27 with respect to the shaft 25 imparts -a set or corresponding resistance to any opposing rotation which may be exerted upon the shaft 25.

The rotation of the collar 27 with respect to the shaft 25 may be accomplished by means of a detent or pin 32 which is removably receivable within a plurality of equally spaced-apart radial apertures 33 formed in the flanged portions 24 of said collar 27, the said detent or pin 32 being provided with an expanded annular portion 34 which is seatable upon annular shoulders 35 formed in each of said radial apertures 33. The said pin 32 is also slidably received in a slot 36 formed in the hollow drum 22.

It will be noted from the foregoing arrangement that one end of the coiled torsion spring 3% may be rotated with respect to the shaft 25 by simply rotating the detent or pin 32 so that it will be displaced from an initial position at one end of the slot 36 to the other end thereof. Upon such rotation, another of the said radial apertures 33 is aligned with that end of the slot which was occupied by the detent or pin 32 prior to its aforesaid rotation. To maintain this position, another of said pins 32 may be inserted in said last-mentioned aperture so as to be biased against the edge of the slot by the force of the torsion spring. Further rotation of the collar 27 with respect to the shaft 25 may also be accomplished in a similar manner so as to successively any of the apertures 33 with the ends of the slot 36 and produce any desired amount of torsion in the spring 34 The shaft is provided with a pair of opposing flanged pulleys 37 secured to the ends or the shaft by suitable fastening elements such as transverse pins 38, the pulleys 37 being provided with two pair of outer and inner cover plates 39, 40 secured by suitable bolts 41a to the opposing guide rails 17.

The external periphery of each of the pulleys 37 receives a flexible member, such as a flexible band 46, which is secured to said pulley, as by a suitable pin 37a engaged with a portion of said band disposed within a radial notch 37]) provided in each of the pulleys 37. In this manner, the carriage plates are supported within :the vertical trackways 15, 16 and since said plates 39 and 40 are alfixed to the carrier assembly, as by bolts 47, the said carrier assembly is also supported between said trackways.

It will be seen from this arrangement that the coiled spring 30 may be initially deflected to any desired extent by rotation of the detent or pin 32. Such deflection of the torsion spring 30 together with any corresponding change of tension of the band 46 will vary the lifting force applied to the carrier platform to accommodate items of different Weights.

The position of each of the bands 45 with respect to the center of each pulley 37 may be varied by the following described mechanism. Thus, the outer and inner cover plates 39, 45} are provided with arcuate extensions 39a, 40a respectively disposed rearwardly of the upright frame assembly 11. A reel 41 is disposed between each pair of cover plates 39, 40, the said reel 41 being secured to a shaft 42 extending through the cover plates 39, 40. A generally U-shaped handle 43, including a pair of substantially parallel mins 44- and an intermediate connecting member 45, is disposed between the opposing inner cover plates 49, the said arms 44 being secured, as by welding to the shafts '42. Said handle 43 may be manually engaged to permit movement of the self-leveling device as a whole, as by pushing, for example, and may also be used for Winding of the band 46 and unwinding thereof from the pulleys 37 in the manner hereafter described. The aforesaid band 46 is disposed upon the reel 4-1 and secured thereto, as by a set screw 50 engaged with a portion of said tape disposed in radial notch 51 provided in, said reel 4-1. The said tape 46 is Wound upon each reel 4'1 by rotating the handle 43 as, for example, in the direction indicated by the arrow shown in its vicinity in FIG- URE 3, thereby causing said handle to occupy extreme positions such as those indicated in solid and in broken lines in said figure. At the same time, said band 46 is correspondingly unwound from the pulleys 37.

It will be observed that when the handle '43 is not being employed for the winding of the reel 41, as aforesaid, it may be locked in its extreme rearward position shownin solid lines in FIGURE 3, by means of a pair of transverse screws 52, which project through the arcuate extensions 39a, ida of the outer and inner cover plates 39, 40, the said arcuate extensions being maintained in spaced relation with respect to each other by a collar 53 disposed intennediately of each pair of said extensions, the said arcuate extensions sea of the inner cover plates 40 also being maintained in spaced relation with respect to offset portions 54 of the arms 44 by a collar 55 disposed between said arcuate extensions 45m and said offset portions 54 of the arms 44. The screws 52 are threadedly engaged with the handle 43 when it is blocked against rotation, but may be removed to permit the rotation of the handle and winding of the band 44? upon the reels 41 to any desired extent.

In this way, the moment arm of the band 46 with respect to the axis of each of the pulleys 37 may be preset as desired.

With this arrangement, any given weight placed upon the platform of the carrier assembly will accomplish a corresponding deflection of the band and of the carriage plate and carrier assembly, as, for example, to the position depicted in broken lines in FIGURE 1 and designated by the numerals 12b and Zilb, the amount of such deflection being determined by the moment arm of said band with respect to the axis of the shaft 37 and the present torsion of the coiled spring 30. tion, it will be particularly noted that the moment arm of the band will shorten as the carrier platform descends and V the counter-pull of the spring increases and the said moment arm will lengthen as the carrier platform rises and the counterpull of the spring decreases.

It will also be noted that in the upper and lower portions of the carriage plate 21 in each trackway, carriage rollers 48 are mounted, each of said rollers being provided with suitable flanged portion for engagement with the trackways. As may be seen in FIGURES l and 7, the band contacts the periphery of the pulley at a point which is offset with respect to the vertical axis of the carriage plate, thereby canting the carriage roller into contact with the head portions 19 of the guide rails 17 The carriage rollers may be suitably mounted upon the carriage plate by a conventional shaft and nut assembly 49, said mounting permitting rotational movement of the carriage rollers.

With this arrangement, the carrier platform may receive a plurality of articles of equal weights, such as dish racks, the uppermost of said racks being maintained at a predetermined level. When the stacks are composed of a different weight, the level thereof may be adjusted by appropriate setting of the spring drum in conjunction with positioning of the moment arm of the band 46 with respect to the axis of each of the pulleys 37. It will be seen that such adjustment is easily, quickly and conveniently accomplished, and does not require the employment of specialized spring elements, the coiled torsion spring within the spring drum being of conventional design. Moreover, a definite positioning of the carrier platform is accomplished In this connecwithout the necessity of using a delicate or unduly complex mechanism.

It will also be observed that the arcuate extensions 39a of the outer cover plates 39 are provided with at least one vertical slot 56 extending radially of the reel 41 adjacent to each of said arcuate extensions 39a, thereby permitting easy observation of the flexible band 46 disposed thereon. The slot 56 is also provided with a series of linear graduations 57 adjacent to that portion of the band 46 which is wound upon the reel 41., each of said graduations 57 being spaced from the adjacent of said graduations at a distance equal to one or more thicknesses of the band 46, thereby permitting determination of the number of windings of said band 45 upon the reel 41 when the outermost of said windings is gauged against said linear graduations, In this way, the setting or" the reel 41 is easily determined, said setting in turn determining the moment arm of the band with respect to the axis of the pulley 37.

In order to accomplish the initial setting of bands 46 upon reels 41, shaft 25 is first released for rotation free of the action of torsion spring 35?. This release of shaft 25 for free rotation is accomplished by completely withdrawing pin 32 from its position in collar 26. The restraint upon one end of the spring is thus removed and shaft 25 and pulleys 37 are freed from the biasing action of the spring and consequently the entire carrier assembly 12 drops to base under its own weight. The position of each of the bands with respect to the center of each of pulleys 37 may then be adjusted as desired by means of handle 43 which winds the bands on reels 41. When the lever arm has thus been adjusted to the desired point, pin 32 is replaced in the particular aperture 33 of collar 37 in registration with slot 36. This restores the operative connection between shaft 25 and drum 22 through the torsion spring. By continuing the operation of handle 43, the torsion spring is wound as the bands are additionally reeled up. The carrier assembly thus rises under the increased tension of the spring. With the carrier assembly thus elevated, handle 43 is locked in fixed position in the manner heretofore indicated. The torsion spring may then be adjusted to any desired degree of tension by successive insertion and removal of pins 32 in the manner heretofore indicated.

The embodiment of the invention illusuated and described hereinabove has been selected for the purpose of clearly setting forth the principles involved. It will be apparent, however, that the present invention is susceptible to being modified in respect to details of construction, combination and arrangement of parts which may be resorted to without departure from the spirit and scope of the invention as claimed.

I claim:

1. In a self-leveling device comprising a base member, an upright frame supported by said base member, vertically movable carriage means retained within said frame, a platform supported by said carriage means for the receipt of articles thereon, spring-biased pulley means provided on said carriage means, reel means mounted for rotation on said frame, and flexible member means extending between said pulley means and said reel means for supporting said carriage means, said reel means being rotatable to a predetermined position to determine the moment arm between said flexible member means and said spring-biased pulley means; that improvement which comprises handle means for said device, said handle means being operable both to propel said device and to rotate said reel means to wind said flexible member means upon said reel means and to unwind said flexible member means from said spring-biased pulley means.

2. The self-leveling device set forth in claim 1 wherein the handle means is provided with locking means releasably engageable with the frame for securing the handle means against rotation.

3. The self-leveling device set forth in claim 1, wherein the carriage means is provided with a pair of laterally spaced spring-biased pulleys, the frame is provided with a pair of laterally spaced reels and a flexible member extends between each pulley and an associated reel, said handle means extending between said spaced reels.

4. The self-leveling device set forth in claim 3, wherein each reel is mounted upon a shaft which is mounted by said frame and said handle means is secured to both said shafts.

5. The self-leveling device set forth in claim 1, wherein provision is made on said frame for cover means for mounting said reel means in enclosing relation, said cover means having slotted means defined therein adjacent to said reel means for exposing the windings of said flexible member means therein, and graduations provided on said cover means at said slotted means to indicate the amount of said windings.

6. The self-leveling device set forth in claim 4, wherein said handle means is a U-shaped member extending rearwardly of said frame.

References Cited in the file of this patent UNITED STATES PATENTS 2,560,928 Bockius July 17, 1951 2,601,295 Jensen June 24, 1952 2,604,996 Smith July 29, 1952 2,932,057 Pemberton Apr. 12, 1960 2,932,404 Vershbow Apr. 12, 1960 

1. IN A SELF-LEVELING DEVICE COMPRISING A BASE MEMBER, AN UPRIGHT FRAME SUPPORTED BY SAID BASE MEMBER, VERTICALLY MOVABLE CARRIAGE MEANS RETAINED WITHIN SAID FRAME, A PLATFORM SUPPORTED BY SAID CARRIAGE MEANS FOR THE RECEIPT OF ARTICLES THEREON, SPRING-BIASED PULLEY MEANS PROVIDED ON SAID CARRIAGE MEANS, REEL MEANS MOUNTED FOR ROTATION ON SAID FRAME, AND FLEXIBLE MEMBER MEANS EXTENDING BETWEEN SAID PULLEY MEANS AND SAID REEL MEANS FOR SUPPORTING SAID CARRIAGE MEANS, SAID REEL MEANS BEING ROTATABLE TO A PREDETERMINED POSITION TO DETERMINE THE MOMENT ARM BETWEEN SAID FLEXIBLE MEMBER MEANS AND SAID SPRING-BIASED PULLEY MEANS; THAT IMPROVEMENT WHICH COMPRISES HANDLE MEANS FOR SAID DEVICE, SAID HANDLE MEANS BEING OPERABLE BOTH TO PROPEL SAID DEVICE AND TO ROTATE SAID REEL MEANS TO WIND SAID FLEXIBLE MEMBER MEANS UPON SAID REEL MEANS AND TO UNWIND SAID FLEXIBLE MEMBER MEANS FROM SAID SPRING-BIASED PULLEY MEANS. 